Fix memory leak when a child exits without wait()-ed

Change-Id: I8ad9e20e3f3e6f406548a6c4de2bf4dc07c40b0e
Refs: #1349

kernel/syscall.c

@@ -1346,8 +1346,8 @@ void terminate(int rc, int sig)
 
 				if (child->ppid_parent == proc &&
 						child->status == PS_ZOMBIE) {
-					list_del(&child->hash_list);
-					list_del(&child->siblings_list);
+					list_del_init(&child->hash_list);
+					list_del_init(&child->siblings_list);
 					free_child = 1;
 				}
 				else if (child->ppid_parent == proc) {
@@ -1377,7 +1377,7 @@ void terminate(int rc, int sig)
 						&updatelock);
 
 				if (free_child)
-					kfree(child);
+					release_process(child);
 			}
 			mcs_rwlock_writer_unlock(&resource_set->process_hash->lock[i],
 					&lock);

test/issues/1349/Makefile

@@ -0,0 +1,10 @@
+# Makefile COPYRIGHT FUJITSU LIMITED 2020
+CC?=gcc
+LDFLAGS=-lpthread
+CFLAGS=-Wall -O0 -ggdb3
+
+all: do_fork6
+do_fork6: do_fork6.o
+do_fork6.o: do_fork6.c
+clean:
+	rm -f do_fork6.o do_fork6

test/issues/1349/README

@@ -0,0 +1,18 @@
+==========
+How to run
+==========
+
+(1) cd <mckernel>
+(2) Build McKernel
+(3) cd <mckernel>/test/issues/1349
+(4) make
+(5) sh ./run.sh
+
+============
+What to test
+============
+
+Check for memory leak when child processes exit without reaped by the parent's wait.
+
+--
+README COPYRIGHT FUJITSU LIMITED 2020

test/issues/1349/do_fork6.c

@@ -0,0 +1,288 @@
+/* do_fork6.c COPYRIGHT FUJITSU LIMITED 2020 */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <sys/time.h>
+#include <signal.h>
+#include <pthread.h>
+#include <sys/wait.h>
+#include <linux/futex.h>
+#include <sys/syscall.h>
+#include <string.h>
+#include <errno.h>
+
+#define FORK1()					\
+	do {					\
+		int pid = fork();		\
+		if (pid < 0) {			\
+			onError("fork");	\
+		} else if (pid == 0) {		\
+			printf("grandchild\n");	\
+			exit(0);		\
+		}				\
+	} while (0)
+
+#define FORK10()				\
+	do {					\
+		FORK1();			\
+		FORK1();			\
+		FORK1();			\
+		FORK1();			\
+		FORK1();			\
+		FORK1();			\
+		FORK1();			\
+		FORK1();			\
+		FORK1();			\
+		FORK1();			\
+	} while (0)
+
+#define FORK100()				\
+	do {					\
+		FORK10();			\
+		FORK10();			\
+		FORK10();			\
+		FORK10();			\
+		FORK10();			\
+		FORK10();			\
+		FORK10();			\
+		FORK10();			\
+		FORK10();			\
+		FORK10();			\
+	} while (0)
+
+enum fin_mode {
+	FIN_MODE_NULL,
+	FIN_MODE_EXIT,
+	FIN_MODE_WAIT,
+};
+
+#define MAXNUMTHREADS	256
+#define DEFAULTTIMETOWAIT 500
+
+int argc;
+char **argv;
+int numthreads = 1;
+enum fin_mode fin_mode = FIN_MODE_NULL;
+int timetowait = DEFAULTTIMETOWAIT;
+
+struct timeval timeBeforeFork;
+struct timeval timeBeforeTest;
+struct timeval timeAfterTest;
+
+#define LAPTIME_MS(start, stop) \
+	((stop.tv_sec - start.tv_sec) * 1000 \
+	 + (stop.tv_usec - start.tv_usec) / 1000)
+
+struct Thread {
+	int tid;
+	pthread_t pthread;
+} thread[MAXNUMTHREADS];
+
+pthread_barrier_t barrier;
+
+void onError(char *message)
+{
+	fprintf(stderr,  "%s: %s: %m\n", argv[0], message);
+	exit(-1);
+}
+
+void waitChildren(void)
+{
+	for (;;) {
+		int status = 0;
+		pid_t pid = wait(&status);
+
+		if (pid == -1) {
+			if (errno == ECHILD) {
+				return;
+			} else if (errno == EINTR) {
+				continue;
+			}
+			onError("wait");
+			exit(-1);
+		}
+	}
+}
+
+void examinerProcess(pid_t subject)
+{
+	printf("[%d] I am the examiner for %d.\n", getpid(), subject);
+	waitChildren();
+}
+
+void subjectTask(struct Thread *thread)
+{
+	pthread_barrier_wait(&barrier);
+
+	gettimeofday(&timeBeforeTest, NULL);
+	printf("[%d] setup: %ld ms\n",
+	       thread->tid,
+	       LAPTIME_MS(timeBeforeFork, timeBeforeTest));
+	printf("[%d] START TEST\n", thread->tid);
+
+	FORK100();
+
+	printf("[%d] END FORK\n", thread->tid);
+
+	{
+		struct timespec req, rem;
+
+		req.tv_sec = timetowait / 1000;
+		req.tv_nsec = (timetowait % 1000) * 1000000;
+		if (nanosleep(&req, &rem) < 0) {
+			fprintf(stderr,
+				"nanosleep is interrupted, but ignore\n");
+		}
+	}
+
+	printf("[%d] FINISH CHILDREN\n", thread->tid);
+	switch (fin_mode) {
+	case FIN_MODE_EXIT:
+		exit(0);
+		break;
+	case FIN_MODE_WAIT:
+		waitChildren();
+		exit(0);
+		break;
+	default:
+		break;
+	}
+
+	printf("%d(%d) TEST FAIL OVERRUN\n", thread->tid, fin_mode);
+	gettimeofday(&timeAfterTest, NULL);
+	for (;;)
+		;
+}
+
+void subjectCleanup(void *arg)
+{
+	struct Thread *thread = (struct Thread *)arg;
+
+	printf("[%d] cleanup\n", thread->tid);
+}
+
+void *subjectThread(void *arg)
+{
+	struct Thread *thread = (struct Thread *)arg;
+
+	printf("[%d] I am a %s %d, %lx %lx\n",
+	       getpid(),
+	       __func__,
+	       thread->tid,
+	       thread->pthread,
+	       pthread_self());
+
+	pthread_cleanup_push(subjectCleanup, arg);
+
+	pthread_barrier_wait(&barrier);
+
+	subjectTask(thread); //< no return
+
+	pthread_cleanup_pop(1);
+
+	return NULL;
+}
+
+void createThreads(void)
+{
+	if (pthread_barrier_init(&barrier, NULL, numthreads)) {
+		onError("pthread_barrier_init fail");
+	}
+
+	int i;
+
+	for (i = 1; i < numthreads; i++) {
+		int rval;
+
+		thread[i].tid = i;
+		rval = pthread_create(&thread[i].pthread,
+				      NULL,
+				      subjectThread,
+				      &thread[i]);
+		if (rval) {
+			onError("pthread_create fail");
+		}
+	}
+	thread[0].tid = 0;
+	thread[0].pthread = pthread_self();
+	subjectThread(&thread[0]);
+}
+
+int main(int _argc, char **_argv)
+{
+	pid_t pid;
+
+	argc = _argc;
+	argv = _argv;
+
+	printf("DO FORK6\n");
+
+	int i;
+
+	for (i = 1; i < argc; i++) {
+		if (strcmp("-nt", argv[i]) == 0) {
+			i++;
+			if (i < argc) {
+				numthreads = atoi(argv[i]);
+				continue;
+			}
+			fprintf(stderr, "%s: num threads required\n", argv[0]);
+			exit(-1);
+		}
+		if (strcmp("-mode-exit", argv[i]) == 0) {
+			fin_mode = FIN_MODE_EXIT;
+			continue;
+		}
+		if (strcmp("-mode-wait", argv[i]) == 0) {
+			fin_mode = FIN_MODE_WAIT;
+			continue;
+		}
+		if (strcmp("-t", argv[i]) == 0) {
+			i++;
+			if (i < argc) {
+				timetowait = atoi(argv[i]);
+				continue;
+			}
+		}
+		fprintf(stderr,
+			"Usage: %s"
+			" -nt <num threads>"
+			" -t <time to wait(msec)>"
+			" {-mode-exit | -mode-wait}\n",
+			argv[0]);
+		exit(-1);
+	}
+
+	if (numthreads < 1 || numthreads > MAXNUMTHREADS) {
+		fprintf(stderr, "%s: invalid num threads\n", argv[0]);
+		exit(-1);
+	}
+
+	if (fin_mode == FIN_MODE_NULL) {
+		fprintf(stderr, "%s: invalid mode\n", argv[0]);
+		exit(-1);
+	}
+
+	printf("NUMTHREADS: %d\n", numthreads);
+	printf("TIMETOWAIT: %d msec\n", timetowait);
+	printf("MODE: %s\n",
+	       (fin_mode == FIN_MODE_EXIT) ? "exit" :
+	       (fin_mode == FIN_MODE_WAIT) ? "wait" :
+	       "null");
+
+	pid = fork();
+	if (pid < 0) {
+		onError("fork");
+	} else if (pid == 0) {
+		createThreads(); //< no return
+		//joinThreads();
+	} else {
+		examinerProcess(pid);
+		printf("FINISH PARENT\n");
+	}
+	return 0;
+}

test/issues/1349/result.log

@@ -0,0 +1,16 @@
+[root@localhost mckernel]# cd test/issues/1349/
+[root@localhost 1349]# make
+cc -Wall -O0 -ggdb3   -c -o do_fork6.o do_fork6.c
+cc -lpthread  do_fork6.o   -o do_fork6
+[root@localhost 1349]# sh run.sh
+mcstop+release.sh ... done
+mcreboot.sh -c 12-59 -m 512M@4 ... done
+(an omission)
+[0] END FORK
+grandchild
+[0] FINISH CHILDREN
+FINISH PARENT
+OK
+
+--
+result.log COPYRIGHT FUJITSU LIMITED 2020

test/issues/1349/run.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+# run.sh COPYRIGHT FUJITSU LIMITED 2020
+test_dir=$(dirname "${BASH_SOURCE[0]}")
+. "${test_dir}/../../common.sh"
+
+# init
+meminfo="/sys/devices/virtual/mcos/mcos0/sys/devices/system/node/node0/meminfo"
+"${MCEXEC}" 0 ./do_fork6 -nt 1 -t $((1000 * 10)) -mode-wait
+sleep 1
+exp_free_mem=`cat "$meminfo" | grep MemFree:`
+
+# run
+"${MCEXEC}" 0 ./do_fork6 -nt 1 -t $((1000 * 10)) -mode-wait
+sleep 1
+free_mem=`cat "$meminfo" | grep MemFree:`
+if [ "$exp_free_mem" != "$free_mem" ]; then
+	echo "NG: detected memory leak."
+	exit -1
+fi
+
+"${MCEXEC}" 0 ./do_fork6 -nt 1 -t $((1000 * 10)) -mode-exit
+sleep 1
+free_mem=`cat "$meminfo" | grep MemFree:`
+if [ "$exp_free_mem" != "$free_mem" ]; then
+	echo "NG: detected memory leak."
+	exit -1
+fi
+
+echo "OK"